Given: 27.375 g HNO₃ and 47.0 g Sr(OH)₂ and total volume of 1.2 L
Reaction: 2HNO₃ (aq) + Sr(OH)₂ (aq) ⇒ Sr(NO₃)₂ (aq) + 2HOH (l)
Net ionic equation: 2H⁺ (aq) + 2OH⁻ (aq) ⇒ 2HOH (l)

Find the final concentration of OH⁻ ions.